Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section. The present disclosure relates to a fixing unit for use in image forming apparatuses, possibly including copying machines, printers, facsimile machines, and multifunction peripherals, among other possibilities. In particular, the present disclosure relates to an image forming apparatus including a fixing unit that separates a recording medium from the surface of a heating member.
In some embodiments, a fixing unit may include an unfixed toner image between a heating member and a pressing member. A recording medium may be fed to the fixing unit such that the heating member fuses toner on the recording medium by a heating action. In addition, the pressing member may fix the fused toner image onto the recording medium by a pressing action.
In some instances, this fixing unit may sometimes have a separating member with a separation claw to prevent the recording medium from winding around the heating member. The separating member may be mounted to the casing of the fixing unit in such a manner that it opposes (e.g., prevents, averts, and/or stops) the surface of the recording medium from coming into contact with the heating member, possibly while keeping a predetermined distance between them.
An example of the fixing unit includes a first casing and a second casing. A heating roller and a pressure roller are rotatably fitted (e.g., rotated and fitted) in the first casing. A separating member is rotatably fitted in the second casing. The separating member includes a separation claw and a rotating shaft.
A spring member may contract to “urge” (e.g., move, pull, and/or lower) the separation claw toward the surface of the heating roller provided between the separating member and the second casing. The second casing has a slot and a bearing disposed inside the slot. The rotating shaft of the separating member has a second shaft having a flat portion and an arc portion. The outer circumference of the rotating shaft has a protruding portion with a curvature. The second casing has a diagonal rib which opposes the protruding portion by making contact with it when the rotating shaft is rotated against the urging (e.g., contracting) force of the spring member. When the separating member is to be mounted to the second casing, the flat portion of the second shaft is inserted into the opposing slot of the second casing until the arc portion of the second shaft reaches the bearing portion of the second casing. The rotating shaft may be rotated with the arc portion of the second shaft on the bearing portion of the second casing. The rotating shaft may be rotated until the protruding portion of the rotating shaft makes contact with the diagonal rib of the second casing. This allows the rotating shaft to rotate in a predetermined range until the protruding portion makes contact with the diagonal rib.
However, the rotational state of the rotating shaft may be controlled by the spring member and urged toward the diagonal rib. In some instances, the second casing is mounted on the first casing and the rotating shaft is rotated against the contracting force of the spring member. This rotation may cause the protruding portion of the rotating shaft to be separated from the diagonal rib but in a predetermined range such that the separating member may be urged to the surface of the heating roller. As such, the separating member may be mounted so as to come in contact with the surface of the heating roller.
For the fixing unit described above, it is necessary to include the protruding portion on the rotating shaft of the separating member and to utilize the diagonal rib on the second casing. In some instances, such implementations may complicate the configurations of the separating member and the second casing. Furthermore, the rotating shaft of the separating member has to be forced into rotating until the protruding portion of the rotating shaft makes contact with the diagonal rib of the second casing. In addition, when the second casing fitted is mounted to the first casing fitted, the position of the separating member relative to the surface of the heating roller may become unstable, which makes it difficult to mount the separating member. Thus, the improvements described herein provide enhanced solutions involving engineering robustness and mechanical efficiency.